Wire race ball bearing

ABSTRACT

A wire race ball bearing containing two outer and two inner wire race rings, the distance between the inner races being smaller than the distance between the outer races, whereby the axes of rotation of the balls are kept unchanged when the bearing is subjected to an uneven axial load.

United States Patent Jonsson Oct. 24, 1972 [54] WIRE RACE BALL BEARING[72] Inventor: Karl-Erik Arnold Jonsson, Gavle,

[21] Appl. No.: 155,543

[30] Foreign Application Priority Data June 24, 1970 Sweden ..8737/70[52] US. Cl ..308/216 [51] Int. Cl. ..F16c 33/58 [58] Field of Search..308/196, 216, 235

[56] References Cited UNITED STATES PATENTS 3,099,073 7/ 1963 Olson..308/216 Primary ExaminerEdgar W. Geoghegan Assistant Examiner-FrankSusko Attorney-Bauer and Goodman ABSTRACT A wire race ball bearingcontaining two outer and two inner wire race rings, the distance betweenthe inner races being smaller than the distance between the outer races,whereby the axes of rotation of the balls are kept unchanged when thebearing is subjected to an uneven axial load.

2 Claims, 3 Drawing Figures PATENTED 24 I97? 3. 700,845

sum 1 OF 2 Fig.1

IO" II WIRE RACE BALL BEARING BACKGROUND OF THE INVENTION The inventionrelates to a wire race ball bearing of the type which comprises acircular row of balls inserted in an annular ball cage between two outerand two inner wire rings slotted radially to be mounted in correspondinggrooves in stator and rotor members. Further, each wire ring is providedwith a ball race turned onto the balls and formed concave in crosssection. Such ball bearings are especially used for rotors with greatdiameters.

In the prior art, the wire rings of a bearing are generally arrangedsymmetrically in relation to the balls, as seen in a cross section, andin any case the distance between the inner races has been equal to thedistance between the outer races. In some fast moving machines the rotormay be supported by a single wire race ball bearing. If such a singlebearing is subjected to a tipping or a tilting moment during therotation, the load acting on the balls will change its direction twotimes at. each revolution, so that the balls are rolling alternatelyalong the one and the other of the two outer races. As the axes ofrotation of the balls are thus reversed two times during a revolution,rapid sliding motions occur between the balls and the races, and by andby this increased friction causes a faceting of the balls, whichinvolves risk of breakdown.

SUMMARY OF THE INVENTION The invention has for its object to provide awire race ball bearing which eliminates the difficulty mentioned abovein that the axes of rotation of the balls are kept unchangedirrespective of tilting forces which may subject the inner rings to anaxial load. For that purpose, the angle between the perpendicular centerlines of the two inner races is 850, preferably l25, smaller than theangle between the perpendicular center lines of the two outer races.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The invention will beexplained in more detail with reference to the accompanying drawings inwhich:

FIG. 1 shows a cross section through a preferred embodiment of the wirerace ball bearing mounted between two concentric members, one of whichis a rotor while the other is a stator;

FIG. 2 shows a perspective view of a portion of the bearing, the ballcage being omitted;

FIG. 3 is a diagrammatic view of a cross section in which thedistribution of the forces is illustrated at a certain uneven load onthe bearing.

In FIG. 1, 4 designates a cylindrical rotor ring. The exterior surfaceof this ring is formed with a peripheral groove 5 which is T-shaped incross section. The deeper central portion 6 of this groove serves toreceive the inner portion of a ball cage 7. The cylinder 4 is in spacedrelationship surrounded by a coaxial cylinder 8 (a stator) composed bytwo rings; a first ring 9 L- shaped in cross section and threadedinternally, and a second ring 10 threaded externally and screwed intosaid first ring. Opposite to the T-shaped groove 5,6 in the innercylinder 4 the outer cylinder 8 has internally a corresponding T-shapedgroove, one half 11 of which is formed in the ring 10, while the otherhalf 12 is formed in the ring 9.

The ball bearing comprises a number of steel balls 13 which aresupported by two wire rings 14,15 mounted in the groove 5 and two wirerings 16,17 mounted in the groove 11,12. As known in per se, the ballcage 7 I retains the ball equally spaced in relation to each other.

To enable the mounting the ball cage may consist of two semicircularportions which are held together by means of a circlip 19 introduced ina peripheral groove 18 in the outer surface of the cage.

As shown in FIG. 2, the wire rings 14-17 are slotted radially (at 20) tomake possible the mounting in the grooves. Each ring has a rectangularor square cross section with a chamfered comer. The chamfer constitutesa circular ball race which is arcuate and concave in cross section insuch a way that its radius is a little greater than the radius of theballs 13. The wire ring surfaces remote from the balls are supported bythe bottoms and the side walls of the grooves 5,11,12, whereby the ringsare effectively held in place.

According to the invention, the distance between the inner races issmaller than the distance between the outer races. This result isobtained by giving the grooves 5,11,12 and/or the rings 14-17 therequired dimensions. As appears from FIG. 3, the angle a between theperpendicular center lines of the inner races is thus smaller than theangle [3 between the perpendicular center lines of the outer races, andas mentioned above, the difference between said angles a and B may varyfrom 8 to 50, preferably between 15 and 25. For many purposes adifference of about 20 between said angles has proved most suitable. Thegreater angle [3 may preferably not exceed In FIG. 3, it has beenassumed that one of the inner race rings (the ring 15) is subjected to atilting force directed axially, as indicated by the arrow 21. The ring15 is thus pressed against the ball 13 by means of a force representedby vector 22 which is directed along the central perpendicular line ofthe race of said ring 15. The force 22 may be divided in two components;one 23 directed onto the outer race ring 16 along its centralperpendicular line, and the other 24 directed onto the outer ring 17,also along the central perpendicular line. The force 22 acting on theball 13 is thus divided such that the ball is kept in engagement withthe two outer race rings, while a certain inevitable deformation maypossibly cause a little clearance between the ball and the race of thering 14. For the sake of clearness, this clearance is shown exaggeratedin FIG. 3. The result of the distribution of force just described willthus be that, irrespective of the axial force 21 acting on the innerring 15, the ball 13 will continue to rotate about an axis 26 inparallel to the axis of the rotor 4.

If the distance between the outer races had been equal to the distancebetween the inner races, the force 22 would have been transferred to therace of the ring 16 directly, so that no division into force componentswould have occurred. In such a case, the ball would have begun to rotateabout an axis perpendicular to a central perpendicular line common tothe races of the two rings 15,16.

I claim:

-50 smaller than the angle between the center lines perpendicular to theconcave surfaces of the two outer races, whereby the axes of rotation ofthe balls are kept substantially unchanged when tilting forces cause anaxial load on one of the inner rings.

2. Ball bearing according to claim 1, wherein the difference in anglesbetween the center lines is l5-25.

1. A wire race ball bearing comprising a circular row of balls insertedin an annular ball cage between two outer and two inner wire rings whichare slotted radially to be mounted in corresponding grooves in statorand rotor members, each wire ring being provided with a ball race turnedtowards the balls and formed with a surface which is concave in crosssection, characterized in that the angle between the center linesperpendicular to the concave surfaces of the two inner races is by8*-50* smaller than the angle between the center lines perpendicular tothe concave surfaces of the two outer races, whereby the axes ofrotation of the balls are kept substantially unchanged when tiltingforces cause an axial load on one of the inner rings.
 2. Ball bearingaccording to claim 1, wherein the difference in Angles between thecenter lines is 15*-25*.